Animal Diversity Web

Ge­o­graphic Range

Glypte­mys in­sculpta oc­curs in a rel­a­tively small area of east­ern Canada and the north­east­ern United States, from Nova Sco­tia and New Brunswick south through New Eng­land, Penn­syl­va­nia and north­ern New Jer­sey, to north­ern Vir­ginia, and west through south­ern Que­bec, south­ern On­tario, north­ern Michi­gan (north­ern Lower and Upper Penin­su­las), north­ern and cen­tral Wis­con­sin, to east­ern Min­nesota; an iso­lated pop­u­la­tion oc­curs in north­east­ern Iowa. Within this range, this tur­tle is gen­er­ally un­com­mon to rare and spot­tily dis­trib­uted (Hard­ing, 1997; Co­nant and Collins, 1998).

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Glypte­mys in­sculpta is al­most in­vari­ably found in as­so­ci­a­tion with mov­ing water (streams, creeks, or rivers), al­though in­di­vid­u­als in some pop­u­la­tions may wan­der con­sid­er­able dis­tances away from water, es­pe­cially in the warmer months. Fe­males may be more ter­res­trial than males in some pop­u­la­tions. Streams with sand or sand and gravel bot­toms are pre­ferred, but rocky stream courses are some­times used, es­pe­cially in the north-east­ern por­tion of the range. Wood tur­tles are often de­scribed as a wood­land species, but in some places they ap­pear to thrive in a mo­saic habi­tat of ri­par­ian woods, shrub or berry thick­ets, swamps, and open, grassy areas. Some un­veg­e­tated or sparsely veg­e­tated patches, prefer­ably with moist, but not sat­u­rated, sand sub­strate, are needed for nest­ing (Hard­ing, 1991; Ernst, Lovich, and Bar­bour, 1994; Hard­ing, 1997; Tut­tle, 1996).

• Habitat Regions
• temperate
• terrestrial
• freshwater

• Terrestrial Biomes
• forest

• Aquatic Biomes
• rivers and streams

Phys­i­cal De­scrip­tion

Adult wood tur­tles have a cara­pace length of 16 to 25 cm (6.3 to 9.8 inches). The brown­ish to gray-brown cara­pace has a low cen­tral keel, and the scutes usu­ally show well-de­fined con­cen­tric growth an­nuli, giv­ing the shell a rough, "sculp­tured" ap­pear­ance that prob­a­bly gave the species its spe­cific name (and per­haps its com­mon name as well). In some spec­i­mens, the ac­cu­mu­lated an­nuli may give each cara­pace scute a some­what flat­tened pyra­mi­dal shape (though this char­ac­ter has been over-em­pha­sized in some ear­lier lit­er­a­ture). The cara­paces of older spec­i­mens may be worn quite smooth. The ver­te­bral scutes some­times dis­play ra­di­at­ing yel­low streaks, or yel­low pig­ment may be re­stricted to the keel. The hin­ge­less plas­tron is yel­low with a black blotch at the rear outer cor­ner of each scute; there is a V-shaped notch at the tail. Plas­tral scutes dis­play promi­nent an­nuli, though, as with the cara­pace, these can be worn smooth over time.

(Note: Count­ing the scute an­nuli, or "growth rings," can offer a rea­son­able es­ti­mate of age in a ju­ve­nile an­i­mal, but this method be­comes in­creas­ingly un­re­li­able as the spec­i­men ap­proaches and then at­tains ma­tu­rity. In older an­i­mals, growth, and thus the for­ma­tion of an­nuli, may es­sen­tially cease; how­ever, count­ing scute an­nuli will usu­ally pro­vide a re­li­able min­i­mum age for a spec­i­men.)

The head of the Wood Tur­tle is black, oc­ca­sion­ally with light dots or other mark­ings; the scales on the upper legs are black to mot­tled brown, while the skin on the throat, lower neck, and on the lower sur­faces of the legs can be yel­low, or­ange, or or­ange-red to salmon-red, some­times speck­led with darker pig­ment. This skin color varies be­tween lo­cal­i­ties, and shows some re­gional vari­a­tion, with yel­low to yel­low-or­ange pre­dom­i­nat­ing in the west­ern (Great Lakes) part of the range, and or­ange to red­dish skin color char­ac­ter­iz­ing east­ern spec­i­mens (Hard­ing, 1997).

Hatch­ling Wood Tur­tles have nearly cir­cu­lar cara­paces that range in length from 2.8 to 3.8 cm (1.1 to 1.5 inches); their tails are nearly as long as the cara­pace. At hatch­ing they are a uni­form brown or gray color dor­sally; the brighter ju­ve­nile and adult col­oration de­scribed above is at­tained dur­ing the first full year of growth (Hard­ing, 1997).

Com­pared to fe­males, adult male G. in­sculpta tend to have wider heads and higher, more elon­gate and domed, cara­paces; the plas­tron is con­cave (de­pressed) in the cen­ter, and their tails are thicker and longer, with the vent (cloa­cal open­ing) be­yond the edge of the cara­pace when the tail is ex­tended. Com­pared to males, adult fe­males tend to have lower and wider, more flar­ing cara­paces; the plas­tron is flat to slightly con­vex, the tail is nar­rower and slightly shorter, with the vent sit­u­ated be­neath the edge of the cara­pace when the tail is ex­tended (Ernst, Lovich, and Bar­bour, 1994; Hard­ing, 1997).

• Other Physical Features
• ectothermic
• bilateral symmetry

Re­pro­duc­tion

Male wood tur­tles form dom­i­nance hi­er­ar­chies in the wild, and will often ag­gres­sively at­tack other males; fe­males also ex­hibit ag­gres­sive be­hav­ior, which can be di­rected both to­ward males and other fe­males. Older, larger males tend to be dom­i­nant over smaller in­di­vid­u­als, and also have bet­ter suc­cess in fer­til­iz­ing eggs (Kauf­mann, 1992).

Courtship may in­clude a mat­ing "dance" in which the male and fe­male face each other and swing their heads back and forth; per­haps more fre­quently the male sim­ply pur­sues the fe­male while nip­ping at her limbs and shell and then mounts her cara­pace. While thus po­si­tioned, the male may nip at the fe­male's head and often thumps the fe­male's cara­pace by straight­en­ing and then flex­ing his front limbs, and drop­ping his plas­tron onto the fe­male's shell. Cop­u­la­tion usu­ally oc­curs in shal­low water on a slop­ing stream bank, though courtship may be ini­ti­ated on land. Mat­ing may occur at any time dur­ing the ac­tive sea­son, but is prob­a­bly most fre­quent in spring and fall, when the tur­tles are more aquatic.

In May or June, fe­male wood tur­tles seek open, sunny nest­ing sites, pre­fer­ring sandy banks ad­ja­cent to mov­ing water when­ever pos­si­ble. The fe­male ex­ca­vates the nest with her hind feet, cre­at­ing a glob­u­lar cav­ity about 5 to 13 cm (2 to 5 inches) deep. Clutch size ranges from 3 to 18 eggs (usu­ally 5 to 13). The eggs are care­fully buried, and the fe­males goes to con­sid­er­able ef­fort to smooth and ob­scure the nest site, but then de­parts, of­fer­ing no fur­ther care to her off­spring. Only one clutch is pro­duced each year, and fe­males may not re­pro­duce every year (Hard­ing, 1977, 1991, 1997).

Most wood tur­tle eggs never hatch; nest pre­da­tion by rac­coons, skunks, shrews, foxes, and other preda­tors can typ­i­cally re­sult in high losses, some­times ap­proach­ing the en­tire year's re­pro­duc­tive ef­fort for a tur­tle pop­u­la­tion when preda­tor num­bers are high. In a Michi­gan study, 70 to 100 per­cent of nests were typ­i­cally lost each year, mostly to rac­coons. For eggs for­tu­nate enough to es­cape de­tec­tion, in­cu­ba­tion re­quires from 47 to 69 days, de­pen­dent mostly on tem­per­a­ture and mois­ture con­di­tions in the nest. Hatch­ling G. in­sculpta gen­er­ally emerge from their nests in late Au­gust or Sep­tem­ber and move to water. They ap­pear not to over­win­ter in the nest, as oc­curs in some other fresh­wa­ter tur­tle species (Ernst, Lovich, and Bar­bour, 1994; Hard­ing, 1997: Tut­tle, 1996).

In this species, the sex of the hatch­ling is in­de­pen­dent of in­cu­ba­tion tem­per­a­ture, a de­par­ture from the trend in closely re­lated emy­did species (such as Clem­mys gut­tata and Emy­doidea blandingii) in which em­bry­onic sex dif­fer­en­ti­a­tion is di­rectly re­lated to nest tem­per­a­tures dur­ing the mid­dle third of the in­cu­ba­tion pe­riod (Ewert and Nel­son, 1991).

Wood tur­tles in the wild usu­ally reach sex­ual ma­tu­rity be­tween 14 and 20 years of age; in a Michi­gan study, most re­pro­duc­tive adults were in their third and fourth decade of life. Max­i­mum lifes­pan in the wild is un­known, but can prob­a­bly ex­ceed the age of 58 ob­tained by a cap­tive spec­i­men (Ernst, Lovich, and Bar­bour, 1994; Hard­ing 1991, 1997).

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)

• Average age at sexual or reproductive maturity (female)
  Sex: female

  5840 days

  AnAge

• Average age at sexual or reproductive maturity (male)
  Sex: male

  5840 days

  AnAge

Lifes­pan/Longevity

• Range lifespan
  Status: captivity

  58 (high) hours

• Average lifespan
  Status: captivity

  12.5 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  60.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Wood Tur­tles are di­ur­nal an­i­mals and spend much of their ac­tive time bask­ing, whether on emer­gent logs and other de­bris along or over wa­ter­ways, or on land, while hid­den in grass or shrub thick­ets. As a species they are well adapted for the cool-tem­per­ate cli­mate found through­out much of their range, and in­di­vid­ual tur­tles can ob­tain body tem­per­a­tures well above the air tem­per­a­ture by care­fully ori­ent­ing their shells to­wards the sun while main­tain­ing a low pro­file out of the wind. Bask­ing not only fa­cil­i­tates ther­moreg­u­la­tion, but also al­lows vi­t­a­min D syn­the­sis, and un­doubt­edly helps dis­lodge ex­ter­nal par­a­sites such as leeches.

Wood Tur­tles hi­ber­nate in win­ter (Oc­to­ber through April in north­ern Michi­gan), gen­er­ally on the bot­tom in the shal­lows of streams and rivers where the water will not freeze. Ter­res­trial hi­ber­na­tion has been re­ported, but is ap­par­ently the ex­cep­tion (Ernst, Lovich, and Bar­bour, 1994; Hard­ing, 1997).

In­di­vid­ual Wood Tur­tles tend to re­main within a lin­ear (stream-based) home range of about 1 to 6 hectares (2.5 to 15 acres), though some in­di­vid­u­als may move con­sid­er­ably greater dis­tances, using stream val­leys as dis­per­sal cor­ri­dors. Most Wood Tur­tles re­main in or within a short dis­tance of mov­ing water through­out the year, de­spite a ten­dency to move and for­age ter­res­tri­ally dur­ing the warmer months (Hard­ing, 1997; Tut­tle, 1996). Eighty-four per­cent of the New York G. in­sculpta ar­ti­fi­cially dis­placed over­land less than 2 km were able to re­turn to their home ranges, but only 17 per­cent of those dis­placed more than 2 km were able to re­turn (Car­roll and Ehren­feld, 1978). How­ever, a Wood Tur­tle dis­placed 8 km up­stream along a river re­turned home in two months (Hard­ing and Bloomer, 1979).

Wood Tur­tles are phys­i­cally quite agile and re­port­edly are un­usu­ally in­tel­li­gent (for tur­tles). One re­port found that Wood Tur­tles in the lab­o­ra­tory were able to learn mazes about as well as rats under sim­i­lar con­di­tions (Tin­klepaugh, 1932), but many re­ports on Wood Tur­tle in­tel­li­gence are anec­do­tal and based on the sub­jec­tive opin­ion of the ob­server. Per­haps be­cause they have evolved be­hav­ioral adap­ta­tions that allow them to move with ease be­tween ri­par­ian aquatic habi­tats and wooded ter­res­trial habi­tats, Wood Tur­tles may ap­pear more in­tel­li­gent to a human ob­server than would other tur­tle species that are adapted for less vari­able habi­tats (Ernst, Lovich, and Bar­bour, 1994; Hard­ing, pers.​obs.).

• Key Behaviors
• terricolous
• natatorial
• diurnal
• motile
• solitary
• territorial

Food Habits

Glypte­mys in­sculpta is an om­niv­o­rous species that can feed both in or out of water. Nat­ural foods re­ported for the species in­clude leaves and flow­ers of var­i­ous herba­ceous and woody plants (vi­o­let, straw­berry, rasp­berry, wil­low), fruits (berries), fungi, slugs, snails, worms, and in­sects. They are usu­ally slow, de­lib­er­ate feed­ers, and seem in­ca­pable of cap­tur­ing fish or other fast-mov­ing prey, though they will op­por­tunis­ti­cally con­sume young mice or eggs, or scav­enge dead an­i­mals (Ernst, Lovich, and Bar­bour, 1994; Hard­ing, 1997)

Wood Tur­tles in some pop­u­la­tions are known to cap­ture earth­worms by thump­ing the ground with their forefeet or the front of the plas­tron. It is thought that the worms may mis­take the vi­bra­tions caused by this thump­ing for the ap­proach of a mole or per­haps the ad­vent of a hard rain, and thus come to the sur­face, only to be grabbed by the hun­gry tur­tle (Hard­ing and Bloomer, 1979; Kauf­mann, et al., 1989; Ernst, Lovich, and Bar­bour, 1994).

• Primary Diet
• omnivore

• Animal Foods
• eggs
• carrion
• insects
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms
• aquatic crustaceans

• Plant Foods
• leaves
• roots and tubers
• fruit
• flowers

• Other Foods
• fungus

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Wood Tur­tles were once har­vested ex­ten­sively for human food (in the east) and for the bi­o­log­i­cal sup­ply trade (es­pe­cially in the west­ern Great Lakes area), and in the last few decades they have been mer­ci­lessly ex­ploited for the pet trade range-wide. None of these ac­tiv­i­ties are sus­tain­able in the long-term; most pop­u­la­tions of Wood Tur­tles are now greatly re­duced from for­mer num­bers, and many have been to­tally ex­tir­pated (Hard­ing, 1991, 1997).

• Positive Impacts
• pet trade
• food
• body parts are source of valuable material
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

This species is harm­less to human in­ter­ests and val­ues.

Con­ser­va­tion Sta­tus

Glypte­mys in­sculpta dis­plays a num­ber of life his­tory traits that make it es­pe­cially vul­ner­a­ble to ex­ploita­tion and habi­tat al­ter­ation by hu­mans. In this and many other tur­tle and tor­toise species, low re­pro­duc­tive rates (low clutch size and/or high nest and hatch­ling mor­tal­ity) and de­layed sex­ual ma­tu­rity are nor­mally bal­anced by rel­a­tively high sur­vivor­ship of older ju­ve­niles and adults, and a long adult re­pro­duc­tive lifes­pan. It has been demon­strated that such species have vir­tu­ally no har­vestable sur­plus in their pop­u­la­tions (as­sum­ing the de­sir­abil­ity of pop­u­la­tion sta­bil­ity), and any fac­tor (nat­ural or hu­man-caused) which re­duces the nor­mally high sur­vivor­ship of older ju­ve­niles and ma­ture adults will re­sult in a de­clin­ing or even ex­tir­pated pop­u­la­tion. In ad­di­tion, these tur­tle pop­u­la­tions will pre­dictably be very slow in re­cov­er­ing from any fac­tor which sig­nif­i­cantly re­duces num­bers of ma­ture in­di­vid­u­als. The Wood Tur­tle may be equally, or even more vul­ner­a­ble than cer­tain other well-stud­ied tur­tle species (such as Emy­doidea blandingii) in this re­gard (Con­g­don et al., 1993; Hard­ing, 1991, and un­publ. data).

Di­rect re­moval by hu­mans is the pri­mary threat to the species in some por­tions of the Wood Tur­tle's range. Re­moval can take the form of road mor­tal­ity, shoot­ing of bask­ing tur­tles by van­dals, com­mer­cial poach­ing for the pet trade, or just in­ci­den­tal col­lec­tion by stream-based recre­ation­ists such as ca­noeists and fish­er­men. In one study (Gar­ber and Burger, 1995), a pre­vi­ously un­ex­ploited pop­u­la­tion of Wood Tur­tles de­clined to vir­tual ex­tir­pa­tion within a decade of being ex­posed to human recre­ation­ists. Glypte­mys in­sculpta is legally pro­tected from com­mer­cial col­lect­ing prac­ti­cally range-wide at pre­sent, and col­lec­tion for per­sonal use is at least reg­u­lated, if not pro­hib­ited, by most of the states and provinces where it oc­curs.

Wood Tur­tles have also suf­fered greatly from habi­tat loss and degra­da­tion. While the species seems some­what tol­er­ant of mod­est tim­ber har­vest and agri­cul­tural ac­tiv­ity in its habi­tat, in­ten­sive forestry, farm­ing, or in­dus­trial or res­i­den­tial de­vel­op­ment in the ri­par­ian zone can se­verely im­pact Wood Tur­tles. In­ten­sive, mech­a­nized agri­cul­ture can re­sult in maim­ing and deaths of Wood Tur­tles due to im­pacts from farm ma­chin­ery (Saumure and Bider, 1998). Cer­tain fish man­age­ment prac­tices that in­volve re­moval ("sta­bi­liza­tion") of sand bank nest­ing sites along north­ern rivers is a rel­a­tively re­cent threat that can re­duce re­pro­duc­tive op­por­tu­ni­ties for this and other tur­tle species. An ad­di­tional threat is the re­cent in­crease in num­bers of "hu­man-sub­si­dized" preda­tors, par­tic­u­larly rac­coons (Pro­cyon lotor), which not only de­stroy tur­tle eggs and hatch­lings, but can also kill or maim adult tur­tles (Hard­ing, 1985; 1991, 1997, pers.​obs.).

The long-term fu­ture for this species is bleak un­less its ri­par­ian habi­tats are pro­tected and the an­i­mals them­selves are left undis­turbed. Wood tur­tles are listed as vul­ner­a­ble by the IUCN and spe­cial con­cern in the state of Michi­gan, and they are in CITES ap­pen­dix II.

• IUCN Red List

  Vulnerable
  More information

• IUCN Red List

  Vulnerable
  More information

• US Federal List

  No special status

• CITES

  Appendix II

• State of Michigan List

  Special Concern

Other Com­ments

Wood Tur­tles had a more southerly dis­tri­b­u­tion dur­ing the Late Pleis­tocene ("ice age"), with fos­sils being de­scribed from Ten­nessee and Geor­gia (Ernst, Lovich, and Bar­bour, 1994).

The old­est fos­sil Wood Tur­tle ap­pears to be a nearly com­plete shell of an adult male spec­i­men found in late Hemphillian de­posits (late Miocene epoch) in Ne­braska. This fos­sil, which is ap­prox­i­mately 6 mil­lion year old, will be de­scribed by its dis­cov­erer, Mr. Shane Tucker, and Dr. Michael Voorhies of the Uni­ver­sity of Ne­braska (Voorhies, pers. comm., June 2000).

The re­la­tion­ships of the Wood Tur­tle to its rel­a­tives in the sub­fam­ily emy­d­i­nae (in the gen­era Clem­mys, Emys, Emy­doidea, and Ter­rapene) have been re­cently stud­ied; the genus Clem­mys, as long sus­pected, was found to be pa­ra­phyletic (Bick­ham et al., 1996; Burke et al., 1996; Feld­man and Parham, 2001). Ac­cord­ing to the lat­est pub­lished re­vi­sions, the Wood Tur­tle will now be com­bined with its clos­est rel­a­tive, the Bog tur­tle (Clem­mys muh­len­bergii), in the genus Glypte­mys; the cor­rect sci­en­tific names for these tur­tles are now Glypte­mys in­sculpta and Glypte­mys muh­len­bergii, re­spec­tively, al­though it will pre­dictably take some time be­fore the new com­bi­na­tions are uni­ver­sally used and rec­og­nized. The Spot­ted Tur­tle, Clem­mys gut­tata, is the only species re­main­ing in the genus Clem­mys (Hol­man and Fritz, 2001; Feld­man and Parham, 2002).

Hy­brids be­tween the Wood Tur­tle and the Bland­ing's tur­tle, Emy­doidea blandingii, have re­cently been de­scribed (Hard­ing, 1999).

Con­trib­u­tors

David Ar­mitage (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

James Hard­ing (au­thor), Michi­gan State Uni­ver­sity, James Hard­ing (ed­i­tor), Michi­gan State Uni­ver­sity.

Ref­er­ences

Bick­ham, J., T. Lamb, P. Minx, J. Pat­ton. 1996. Mol­e­c­u­lar sys­tem­at­ics of the genus *Clem­mys* and the in­ter­generic re­la­tion­ships of emy­did tur­tles. Her­peto­log­ica, 52(1): 89-97.

Burke, R., T. Leu­teritz, A. Wolf. 1996. Phy­lo­ge­netic re­la­tion­ships of emy­dine tur­tles. Her­peto­log­ica, 52(4): 572-584.

Car­roll, T., D. Ehren­feld. 1978. In­ter­me­di­ate-range hom­ing in the wood tur­tle, *Clem­mys in­sculpta*. Copeia, 1978: 117-126.

Co­nant, R., J. Collins. 1998. A Field Guide to Rep­tiles and Am­phib­ians of East­ern and Cen­tral North Amer­ica, Third Ed., Ex­panded. Boston and New York: Houghton Mif­flin.

Con­g­don, J., A. Dun­ham, R. van Loben Sels. 1993. De­layed sex­ual ma­tu­rity and de­mo­graph­ics of Bland­ing's Tur­tles (*Emy­doidea blandingii*): Im­pli­ca­tions for con­ser­va­tion and man­age­ment of long-lived or­gan­isms. Con­serv. Biol., 7(4): 826-833.

Ernst, C., J. Lovich, R. Bar­bour. 1994. Tur­tles of the United States and Canada. Wash­ing­ton, D.C.: Smith­son­ian In­sti­tu­tion Press.

Ewert, M., C. Nel­son. 1991. Sex de­ter­mi­na­tion in tur­tles: Di­verse pat­terns and some pos­si­ble adap­tive val­ues. Copeia, 1991: 50-69.

Feld­man, C., J. Parham. 2002. A mol­e­c­u­lar phy­logeny for emy­dine tur­tles: tax­o­nomic re­vi­sion and the evo­lu­tion of shell ki­ne­sis. Mol­e­c­u­lar Phy­lo­ge­net­ics and Evo­lu­tion, 22(3): 388-398.

Feld­man, C., J. Parham. 2001. Mol­e­c­u­lar sys­tem­at­ics of emy­dine tur­tles.. Ch­e­lon­ian Con­ser­va­tion and Bi­ol­ogy, 4(1): 194-198.

Gar­ber, S., J. Burger. 1995. A 20-year study doc­u­ment­ing the re­la­tion­ship be­tween tur­tle de­cline and human recre­ation. Eco­log­i­cal Ap­pli­ca­tions, 5(4): 1151-1162.

Hard­ing, J. 1985. Life His­tory Notes: *Clem­mys in­sculpta* (Pre­da­tion and Mu­ti­la­tion). Her­petol. Rev. (SSAR), 16(1): 30.

Hard­ing, J. 1999. Life His­tory Notes: *Clem­mys in­sculpta* and *Emy­doidea blandingii*. Hy­bridiza­tion.. Her­petol. Rev. (SSAR), 30 (4): 225-226.

Hard­ing, J. 1977. Record egg clutches for *Clem­mys in­sculpta*. Her­petol. Rev. (SSAR), 8(2): 34.

Hard­ing, J., T. Bloomer. 1979. The wood tur­tle, *Clem­mys in­sculpta*, a nat­ural his­tory.. HERP: Bull. New York Herp. Soc., 15(1): 9-26.

Hard­ing, J. 1991. A twenty year wood tur­tle study in Michi­gan: im­pli­ca­tions for con­ser­va­tion. Chap­man Uni­ver­sity, Or­ange, Cal­i­for­nia: In: Pro­ceed­ings of the First In­ter­na­tional Sym­po­sium on Tur­tles and Tor­toises: Con­ser­va­tion and Cap­tive Hus­bandry.

Hard­ing, J. 1997. Am­phib­ians and Rep­tiles of the Great Lakes Re­gion. Ann Arbor, Michi­gan: Uni­ver­sity of Michi­gan Press.

Hol­man, J., U. Fritz. 2001. A new emy­dine species from the Mid­dle Miocene (Barstov­ian) of Ne­braska, USA with a new generic arrange­ment for the species of Clem­mys sensu Mc­Dow­ell (1964) (Rep­tilia: Tes­tudines: Emy­di­dae). Zo­ol­o­gis­che Ab­hand­lun­gen Staatliches Mu­seum für Tierkunde Dres­den, 51: 331-354.

Kauf­mann, J. 1992. The so­cial be­hav­ior of wood tur­tles, *Clem­mys in­sculpta*, in cen­tral Penn­syl­va­nia. Her­petol. Monogr., 6: 1-25.

Kauf­mann, J., J. Hard­ing, K. Brew­ster. 1989. Worm stomp­ing by wood tur­tles re­vis­ited.. Bull. Chicago Herp. Soc., 24: 125-126.

Saumure, R., J. Bider. 1998. Im­pact of agri­cul­tural de­vel­op­ment on a pop­u­la­tion of Wood Tur­tles (Clem­mys in­sculpta) in south­ern Que­bec, Canada. Ch­e­lon­ian Con­ser­va­tion and Bi­ol­ogy, 3(1): 37-45.

Tin­klepaugh, O. 1932. Maze learn­ing of a tur­tle. Journ. Comp. Psych., 13: 201-206.

Tut­tle, S. 1996. Mas­ter of Sci­ence The­sis: Ecol­ogy and Nat­ural His­tory of the Wood Tur­tle (*Clem­mys in­sculpta*) in South­ern New Hamp­shire. Keene, New Hamp­shire: An­ti­och New Eng­land Grad­u­ate School, An­ti­och Uni­ver­sity.